Rename Error::IO to Error::Io (#5174)

## Summary

I believe this is by convention (see, e.g., in Rust itself:
https://github.com/search?q=repo%3Arust-lang%2Frust+%2F%28%3F-i%29Io%2F&type=code).

crates/requirements-txt/src/lib.rs

@@ -169,7 +169,7 @@ impl RequirementsTxt {
                 {
                     return Err(RequirementsTxtFileError {
                         file: requirements_txt.to_path_buf(),
-                        error: RequirementsTxtParserError::IO(io::Error::new(
+                        error: RequirementsTxtParserError::Io(io::Error::new(
                             io::ErrorKind::InvalidInput,
                             "Remote file not supported without `http` feature",
                         )),
@@ -182,7 +182,7 @@ impl RequirementsTxt {
                     if client_builder.is_offline() {
                         return Err(RequirementsTxtFileError {
                             file: requirements_txt.to_path_buf(),
-                            error: RequirementsTxtParserError::IO(io::Error::new(
+                            error: RequirementsTxtParserError::Io(io::Error::new(
                                 io::ErrorKind::InvalidInput,
                                 format!("Network connectivity is disabled, but a remote requirements file was requested: {}", requirements_txt.display()),
                             )),
@@ -196,7 +196,7 @@ impl RequirementsTxt {
                 // Ex) `file:///home/ferris/project/requirements.txt`
                 uv_fs::read_to_string_transcode(&requirements_txt)
                     .await
-                    .map_err(RequirementsTxtParserError::IO)
+                    .map_err(RequirementsTxtParserError::Io)
             }
             .map_err(|err| RequirementsTxtFileError {
                 file: requirements_txt.to_path_buf(),
@@ -800,7 +800,7 @@ pub struct RequirementsTxtFileError {
 /// Error parsing requirements.txt, error disambiguation
 #[derive(Debug)]
 pub enum RequirementsTxtParserError {
-    IO(io::Error),
+    Io(io::Error),
     Url {
         source: url::ParseError,
         url: String,
@@ -877,7 +877,7 @@ pub enum RequirementsTxtParserError {
 impl Display for RequirementsTxtParserError {
     fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
         match self {
-            Self::IO(err) => err.fmt(f),
+            Self::Io(err) => err.fmt(f),
             Self::Url { url, start, .. } => {
                 write!(f, "Invalid URL at position {start}: `{url}`")
             }
@@ -945,7 +945,7 @@ impl Display for RequirementsTxtParserError {
 impl std::error::Error for RequirementsTxtParserError {
     fn source(&self) -> Option<&(dyn std::error::Error + 'static)> {
         match &self {
-            Self::IO(err) => err.source(),
+            Self::Io(err) => err.source(),
             Self::Url { source, .. } => Some(source),
             Self::FileUrl { .. } => None,
             Self::VerbatimUrl { source, .. } => Some(source),
@@ -971,7 +971,7 @@ impl std::error::Error for RequirementsTxtParserError {
 impl Display for RequirementsTxtFileError {
     fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
         match &self.error {
-            RequirementsTxtParserError::IO(err) => err.fmt(f),
+            RequirementsTxtParserError::Io(err) => err.fmt(f),
             RequirementsTxtParserError::Url { url, start, .. } => {
                 write!(
                     f,
@@ -1108,7 +1108,7 @@ impl std::error::Error for RequirementsTxtFileError {
 
 impl From<io::Error> for RequirementsTxtParserError {
     fn from(err: io::Error) -> Self {
-        Self::IO(err)
+        Self::Io(err)
     }
 }
 

crates/uv-build/src/lib.rs

@@ -87,7 +87,7 @@ static SETUP_PY_REQUIREMENTS: Lazy<[Requirement; 2]> = Lazy::new(|| {
 #[derive(Error, Debug)]
 pub enum Error {
     #[error(transparent)]
-    IO(#[from] io::Error),
+    Io(#[from] io::Error),
     #[error("Invalid source distribution: {0}")]
     InvalidSourceDist(String),
     #[error("Invalid `pyproject.toml`")]

crates/uv-python/src/discovery.rs

@@ -149,7 +149,7 @@ pub enum PythonSource {
 #[derive(Error, Debug)]
 pub enum Error {
     #[error(transparent)]
-    IO(#[from] io::Error),
+    Io(#[from] io::Error),
 
     /// An error was encountering when retrieving interpreter information.
     #[error(transparent)]

crates/uv-python/src/downloads.rs

@@ -28,7 +28,7 @@ use crate::{Interpreter, PythonRequest, PythonVersion, VersionRequest};
 #[derive(Error, Debug)]
 pub enum Error {
     #[error(transparent)]
-    IO(#[from] io::Error),
+    Io(#[from] io::Error),
     #[error(transparent)]
     ImplementationError(#[from] ImplementationError),
     #[error("Invalid Python version: {0}")]

crates/uv-python/src/managed.rs

@@ -24,7 +24,7 @@ use uv_fs::{LockedFile, Simplified};
 #[derive(Error, Debug)]
 pub enum Error {
     #[error(transparent)]
-    IO(#[from] io::Error),
+    Io(#[from] io::Error),
     #[error(transparent)]
     Download(#[from] DownloadError),
     #[error(transparent)]

crates/uv-python/src/virtualenv.rs

@@ -32,12 +32,12 @@ pub struct PyVenvConfiguration {
 
 #[derive(Debug, Error)]
 pub enum Error {
+    #[error(transparent)]
+    Io(#[from] io::Error),
     #[error("Broken virtualenv `{0}`: `pyvenv.cfg` is missing")]
     MissingPyVenvCfg(PathBuf),
     #[error("Broken virtualenv `{0}`: `pyvenv.cfg` could not be parsed")]
     ParsePyVenvCfg(PathBuf, #[source] io::Error),
-    #[error(transparent)]
-    IO(#[from] io::Error),
 }
 
 /// Locate an active virtual environment by inspecting environment variables.

crates/uv-tool/src/lib.rs

@@ -30,7 +30,7 @@ mod tool;
 #[derive(Error, Debug)]
 pub enum Error {
     #[error(transparent)]
-    IO(#[from] io::Error),
+    Io(#[from] io::Error),
     #[error("Failed to update `uv-receipt.toml` at {0}")]
     ReceiptWrite(PathBuf, #[source] Box<toml::ser::Error>),
     #[error("Failed to read `uv-receipt.toml` at {0}")]
@@ -121,7 +121,7 @@ impl InstalledTools {
         let path = self.tool_dir(name).join("uv-receipt.toml");
         match ToolReceipt::from_path(&path) {
             Ok(tool_receipt) => Ok(Some(tool_receipt.tool)),
-            Err(Error::IO(err)) if err.kind() == io::ErrorKind::NotFound => Ok(None),
+            Err(Error::Io(err)) if err.kind() == io::ErrorKind::NotFound => Ok(None),
             Err(err) => Err(err),
         }
     }

crates/uv-virtualenv/src/lib.rs

@@ -11,7 +11,7 @@ mod virtualenv;
 #[derive(Debug, Error)]
 pub enum Error {
     #[error(transparent)]
-    IO(#[from] io::Error),
+    Io(#[from] io::Error),
     #[error("Failed to determine Python interpreter to use")]
     Discovery(#[from] uv_python::DiscoveryError),
     #[error("Failed to determine Python interpreter to use")]

crates/uv-virtualenv/src/virtualenv.rs

@@ -86,7 +86,7 @@ pub(crate) fn create(
     match location.metadata() {
         Ok(metadata) => {
             if metadata.is_file() {
-                return Err(Error::IO(io::Error::new(
+                return Err(Error::Io(io::Error::new(
                     io::ErrorKind::AlreadyExists,
                     format!("File exists at `{}`", location.user_display()),
                 )));
@@ -103,7 +103,7 @@ pub(crate) fn create(
                 {
                     info!("Ignoring empty directory");
                 } else {
-                    return Err(Error::IO(io::Error::new(
+                    return Err(Error::Io(io::Error::new(
                         io::ErrorKind::AlreadyExists,
                         format!(
                             "The directory `{}` exists, but it's not a virtualenv",
@@ -116,7 +116,7 @@ pub(crate) fn create(
         Err(err) if err.kind() == io::ErrorKind::NotFound => {
             fs::create_dir_all(location)?;
         }
-        Err(err) => return Err(Error::IO(err)),
+        Err(err) => return Err(Error::Io(err)),
     }
 
     let location = location.canonicalize()?;

crates/uv/src/commands/tool/list.rs

@@ -26,7 +26,7 @@ pub(crate) async fn list(
     let installed_tools = InstalledTools::from_settings()?;
     let _lock = match installed_tools.acquire_lock() {
         Ok(lock) => lock,
-        Err(uv_tool::Error::IO(err)) if err.kind() == std::io::ErrorKind::NotFound => {
+        Err(uv_tool::Error::Io(err)) if err.kind() == std::io::ErrorKind::NotFound => {
             writeln!(printer.stderr(), "No tools installed")?;
             return Ok(ExitStatus::Success);
         }

crates/uv/src/commands/tool/uninstall.rs

@@ -27,7 +27,7 @@ pub(crate) async fn uninstall(
     let installed_tools = InstalledTools::from_settings()?.init()?;
     let _lock = match installed_tools.acquire_lock() {
         Ok(lock) => lock,
-        Err(uv_tool::Error::IO(err)) if err.kind() == std::io::ErrorKind::NotFound => {
+        Err(uv_tool::Error::Io(err)) if err.kind() == std::io::ErrorKind::NotFound => {
             if let Some(name) = name {
                 bail!("`{name}` is not installed");
             }
@@ -48,7 +48,7 @@ pub(crate) async fn uninstall(
                     )?;
                     return Ok(ExitStatus::Success);
                 }
-                Err(uv_tool::Error::IO(err)) if err.kind() == std::io::ErrorKind::NotFound => {
+                Err(uv_tool::Error::Io(err)) if err.kind() == std::io::ErrorKind::NotFound => {
                     bail!("`{name}` is not installed");
                 }
                 Err(err) => {